Aluminium magnesium titanate is known as a ceramic excellent in heat resistance. Its production process is disclosed in Example 1 of Patent Reference 1 (W02004/039747, pp. 6-7). In Example 1, a pre-mixture containing a titania source powder, an alumina source powder, a magnesia source powder and a silica source powder is gradually heated up to 700° C., the temperature is kept for 3 hours, thereafter the pre-mixture is heated up to 1000° C. taking 26 hours, then further up to 1400° C. taking 2 hours, and fired at the temperature for hours. According to the process, the pre-mixture is maintained within a temperature range of from 1100° C. to 1350° C. for 1.8 hours in the heating process.
As a process for producing aluminium magnesium titanate, desired is a process capable of producing one having a small coefficient of thermal expansion. For producing aluminium magnesium titanate having a small coefficient of thermal expansion, the pre-mixture maybe fired at a higher temperature, for example, at a temperature not lower than 1500° C.
However, for industrial operation, the firing temperature is preferably lower.